In this study Advanced Grid Stiffened (AGS) composite structures are developed and analyzed for their mechanical properties. It is widely known that these structures possess light weight, high strength, and inherent impact resistance. Because of the advantages mentioned above, the AGS composite structures find many applications in aerospace, ship building and construction industries. The purpose of this study is to manufacture AGS composite structures and analyze AGS composite structures as reinforcement members. A FEA model is also developed and validated with the test results. Parametric analysis is also conducted to investigate the effects of different design parameters on these structures.

The research is divided into five phases. In the first phase, discussions are made about the fabrication of AGS composite structures. A fabrication technique is developed to fabricate a circular cylinder and a square cylinder with orthogonal grids. The second phase, the AGS composite tubes are used to confine concrete. Specimens are prepared and they are subjected to uniaxial compression test, to evaluate the confinement effectiveness of the AGS tube. In the third phase, a FEA model is developed using COSMOS/M software package. In this model, the support of the concrete to the ribs within the bay area is considered as a Winkler foundation. The FEA model is validated using test results. In the fourth phase, the validated model is used to conduct parametric analysis. The effect of various parameters on the structural behavior is evaluated and ways to further improve the structure are found. In the final phase, results are analyzed and discussions are made from the comparisons and general conclusions are drawn accordingly.